JP6064102B1 - Drive shaft, insertion device and insertion device - Google Patents

Abstract

The drive shaft extends along the shaft axis inside the tubular portion, and the drive shaft rotates around the shaft axis in a state where the drive force generated by the drive source is transmitted to the driven portion. . The drive shaft includes a plurality of extending portions and a hard portion. Each of the extending portions extends along the shaft axis. The said hard part is provided in the state pinched | interposed between two said extending parts about the direction along the said shaft axis, and is hard compared with the said extending part.

Description

The present invention relates to a drive shaft that rotates about a central axis in a state where a driving force is transmitted from a driving source to a driven part. The present invention also relates to an insertion device including the drive shaft and an insertion device including the insertion device.

  International Publication No. 2013/038720 discloses an endoscope apparatus including an insertion portion extending along a longitudinal axis and an auxiliary tool (spiral unit) attached to the insertion portion. In this endoscope apparatus, a drive shaft is extended inside an insertion portion (tubular portion). When a driving force is generated by a motor (driving source) provided in a holding unit (operation unit) of the endoscope, the driving force is transmitted to the driving shaft, and the driving shaft rotates about the shaft axis. When the drive shaft rotates, a driving force is transmitted to a rotating body (driven portion) provided in the insertion portion, and the rotating body rotates about the longitudinal axis. When the rotating body rotates with the auxiliary tool attached to the insertion portion, the auxiliary tool rotates about the longitudinal axis together with the rotating body.

  In an insertion device such as International Publication No. 2013/038720, a flexible drive shaft is formed by laminating a plurality of coil layers each formed in a spiral shape around the shaft axis. . For this reason, when the torque acting on the drive shaft increases in a state where the drive force is transmitted from the drive source side to the driven portion side, the amount of twist in the drive shaft increases. In addition, since the drive shaft is formed as described above, the drive shaft extends or contracts in the direction along the shaft axis when the drive shaft rotates about the shaft axis. At this time, if the torque acting on the drive shaft increases, the amount of expansion and contraction of the drive shaft increases. When the drive shaft is rotating, the amount of twist, the amount of extension, and the amount of contraction are increased, which reduces the transmission efficiency of the drive force on the drive shaft.

  The present invention has been made paying attention to the above-mentioned problems, and an object of the present invention is to provide a drive shaft that ensures the transmission efficiency of the driving force from the driving source side to the driven portion side. Moreover, it is providing the insertion apparatus and insertion apparatus provided with the drive shaft.

To achieve the above object, one aspect of the present invention is extended along the central axis by being rotated around the axis of said central shaft by a drive source, the drive for transmitting a driving force to the driven part a shaft, wherein while being extended along a central axis, a plurality of extending portions that are arranged for a direction along the central axis, two of said extending portion for the direction along the central axis While connecting between edge parts , it is provided with the hard part formed harder than the said extension part.

FIG. 1 is a schematic diagram illustrating an endoscope system in which the endoscope apparatus according to the first embodiment is used. FIG. 2 is a schematic diagram illustrating the configuration of the drive shaft according to the first embodiment. FIG. 3 is a cross-sectional view schematically showing the drive shaft according to the first embodiment in a cross section perpendicular to the central axis . FIG. 4 is a schematic diagram illustrating a configuration of a drive shaft according to a first modification of the first embodiment. FIG. 5 is a schematic diagram illustrating a configuration of a drive shaft according to a second modification of the first embodiment. FIG. 6 is a schematic diagram illustrating a configuration of a drive shaft according to the second embodiment. FIG. 7 is a schematic diagram illustrating a configuration of a drive shaft according to a modification of the second embodiment.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an endoscope system 1 in which an endoscope apparatus 2 that is an insertion apparatus of the present embodiment is used.

  As shown in FIG. 1, the endoscope apparatus 2 includes an endoscope 3 that is an insertion device and a spiral unit 20 that is an auxiliary tool. The endoscope 3 includes an insertion portion 5, and the insertion portion 5 has a longitudinal axis C. Here, let the direction along the longitudinal axis C be a longitudinal direction. One side in the longitudinal direction is the tip side (arrow C1 side in FIG. 1), and the side opposite to the tip side is the base side (arrow C2 side in FIG. 1). The insertion portion 5 extends from the proximal end side to the distal end side along the longitudinal axis C, and the operation portion 6 is provided on the proximal end side of the insertion portion 5 in the endoscope 3. The endoscope 3 includes a universal cord 7 having one end connected to the operation unit 6. A scope connector 8 is provided at the other end of the universal cord 7.

  The endoscope system 1 includes an image processing device 11 such as an image processor, a light source device 12 such as a lamp, a drive control device 13, an operation input device 14 such as a foot switch, and a monitor as peripheral device units 10. Display device 15. The universal cord 7 is detachably connected to the peripheral device unit 10 via the scope connector 8. In the endoscope 3, the imaging cable 21 and the light guide 22 extend through the inside of the insertion portion 5, the inside of the operation portion 6, and the inside of the universal cord 7. An imaging element 23 such as a CCD is provided inside the distal end portion of the insertion portion 5. The imaging element 23 images a subject through an observation window 25 provided on the outer surface of the distal end portion of the insertion portion 5. Then, an imaging signal is transmitted to the image processing device 11 via the imaging cable 21, and image processing is performed by the image processing device 11. As a result, a subject image is generated by the image processing device 11, and the generated subject image is displayed on the display device 15. The light emitted from the light source device 12 is guided through the light guide 22. Then, the guided light is irradiated to the subject from the illumination window 26 provided on the outer surface of the distal end portion of the insertion portion 5.

  In the endoscope apparatus 2, the spiral unit 20 is detachably attached to the insertion unit 5 in a state where the insertion unit 5 is inserted into the spiral unit (auxiliary tool) 20. In a state where the spiral unit 20 is attached to the insertion portion 5, the spiral unit 20 is substantially coaxial with the insertion portion 5. The spiral unit 20 includes a tubular tube main body 27 extending along the longitudinal axis C, and a spiral fin 28 protruding toward the outer peripheral side on the outer peripheral surface of the tube main body 27. The spiral fin 28 extends in a spiral shape with the longitudinal axis C as the center. The spiral unit (auxiliary tool) 20 is rotatable around the longitudinal axis C.

  In the endoscope 3, a motor casing 31 is attached to the operation unit 6. An electric motor 32 as a drive source is provided inside the motor casing 31. The electric motor 32 is provided on the proximal end side with respect to the insertion portion 5. One end of electrical wires 33A and 33B is connected to the electric motor 32. The electrical wirings 33 </ b> A and 33 </ b> B are connected to the drive control device 13 through the operation unit 6 and the universal cord 7. The drive control device 13 controls the drive state of the electric motor 32 by controlling the supply state of the drive power to the electric motor 32 based on the operation input from the operation input device 14. The drive control device 13 is provided with a processor or an integrated circuit including a CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit), and a storage medium such as a memory. Driving power is generated by supplying driving power to the electric motor 32. A gear train 35 is attached to the electric motor 32.

A drive shaft 40 extends from the proximal end side toward the distal end side inside the insertion portion 5 that is a tubular portion. The drive shaft 40 extends along a central axis S (substantially parallel to the longitudinal axis C). The base end of the drive shaft 40 is connected to the gear train 35 via a base end side connection member (drive source side connection member) 41.

  The insertion portion 5 includes a base portion 37 and a rotating body (driven portion) 38 attached to the base portion 37 so as to be rotatable about the longitudinal axis C with respect to the base portion 37. The spiral unit (auxiliary tool) 20 is attached to the insertion portion 5 so as to cover the outer peripheral side of the base portion 37 and the rotating body 38. A drive gear 43 is attached to the base portion 37. The inner peripheral surface of the rotator 38 meshes with the drive gear 43, and the drive gear 43 is connected to the rotator 38. The tip of the drive shaft 40 is connected to the drive gear 43 via a tip side connection member (driven portion side connection member) 45.

When a driving force is generated by the electric motor (drive source) 32, the generated driving force is transmitted to the drive shaft 40 via the gear train 35. As a result, the drive shaft 40 rotates about the central axis S , and the driving force is transmitted from the proximal end side (drive source side) to the distal end side (driven portion side) in the drive shaft 40. Then, the driving force is transmitted from the drive shaft 40 to the rotating body 38 through the driving gear 43, whereby the rotating body (driven part) 38 is driven, and the rotating body 38 rotates around the longitudinal axis C with respect to the base part 37. Rotate to. When the rotating body 38 is driven in a state where the spiral unit 20 is attached to the insertion portion 5, the driving force is transmitted from the rotating body (driven portion) 38 to the spiral unit (auxiliary tool) 20. Thereby, the spiral unit 20 rotates about the longitudinal axis C with respect to the base portion 37 together with the rotating body 38. In the present embodiment, when the spiral unit 20 rotates in a state in which a pressing force acts on the inner peripheral side of the spiral fin 28, a propulsive force on the distal end side or the proximal end side acts on the insertion portion 5 and the spiral unit 20. .

FIG. 2 is a diagram showing the configuration of the drive shaft 40, and FIG. 3 shows the drive shaft 40 in a cross section perpendicular to the central axis S. As shown in FIGS. 2 and 3, the drive shaft 40 includes a plurality of (four in this embodiment) coil layers 51 to 54. In the drive shaft 40, the coil layer 51, the coil layer 52, the coil layer 53, and the coil layer 54 are provided in this order from the inner peripheral side to the outer peripheral side, and the outermost layer of the drive shaft 40 is formed by the coil layer 54. Each of the coil layers 51 to 54 is formed in a spiral shape with the central axis S as the center. Each of the coil layers 51 to 54 is preferably opposite to the coil layer (one or two corresponding to 51 to 54) adjacent in the radial direction of the drive shaft 40 in the winding direction. In this case, for example, the coil layers 52 and 54 are on one side around the central axis S (arrow R1 side in FIGS. 2 and 3) from the base end side (drive source side) toward the tip end side (driven portion side). The coil layers 51, 53 are formed in a spiral shape toward the other side (the arrow R2 side in FIGS. 2 and 3) around the central axis S from the proximal end side toward the distal end side. Yes.

In the drive shaft 40, a plurality of extending portions Ei (i = 1, 2,..., K,..., L,..., N, n + 1) and a hard portion Hi (i = 1, 2 in the present embodiment). , ..., k, ..., l, ..., n) extend along the central axis S. The hard portion Hi is formed, for example, by brazing the outer peripheral surface of the outermost coil layer 54 over the entire circumference. In the extended portion Ei, brazing or the like is not performed, and only the coil layers 51 to 54 are formed. For this reason, the hard part Hi is a rigid body that is harder than the extended part Ei and has higher rigidity than the extended part Ei. Further, the extended portion Ei is an elastic body having higher elasticity (flexibility) than the hard portion Hi.

Each of the hard portions Hi is sandwiched between two corresponding extended portions (two corresponding to Ei) in the direction along the central axis S. For example, the hard part Hk is sandwiched between the extension part Ek and the extension part Ek + 1. For this reason, in the drive shaft 40, the extending portions Ei and the hard portions Hi are alternately and serially arranged from the base end side (drive source side) to the distal end side (driven portion side). Therefore, in the drive shaft 40, the hard portion Hi having high rigidity is formed between the base end (end on the drive source side) and the front end (end on the driven portion side). Between each of the hard portions Hi and the adjacent hard portion ( one or two corresponding to Hi) in the direction along the central axis S , there is a corresponding extended portion (one or two corresponding to Ei). ) Is extended. For this reason, the hard portions Hi are provided apart from each other in the direction along the central axis S.

In the present embodiment, the hard portions Hi are disposed at substantially equal intervals in the direction along the central axis S over the entire length from the proximal end to the distal end of the drive shaft 40. That is, the separation distance di (i = 1, 2,..., K,) in the direction along the central axis S between each of the hard portions Hi and the adjacent hard portion ( one or two corresponding to Hi). ..., l, ... n), all the separation distances di are substantially the same. For example, the separation distance dk between the hard part Hk-1 and the hard part Hk is substantially the same as the separation distance dl between the hard part Hl-1 and the hard part Hl.

  Next, operations and effects of the drive shaft 40 and the endoscope apparatus 2 according to the present embodiment will be described. When observing a lumen using the endoscope system 1 (endoscope device 2), a spiral unit (auxiliary tool) 20 is attached to the insertion portion 5, and the insertion portion 5 and the spiral unit 20 are connected to an intestinal tract or the like. Insert into the lumen. The electric motor 32 is driven based on the operation input from the operation input device 14, and the driving force is transmitted to the spiral unit 20 as described above. Thereby, the spiral unit 20 rotates around the longitudinal axis (revolution axis) C. When the spiral unit 20 is rotated in a state where the spiral fin 28 is pressed to the inner peripheral side by the lumen wall, the propulsive force toward the distal end side or the proximal end side (one side along the longitudinal axis C) is inserted into the insertion portion. 5 and the spiral unit 20. The mobility of the insertion portion 5 in the lumen is improved by the driving force.

As described above, the drive shaft 40 is composed of the coil layers 51 to 54 formed in a spiral shape with the central axis S as the center. For this reason, when the drive shaft 40 rotates around the central axis S and the driving force is transmitted from the base end side (drive source side) to the tip end side (driven portion side), the drive shaft 40 is twisted. Occur. In the present embodiment, in the drive shaft 40, a hard portion Hi having high rigidity is provided between a base end (end on the drive source side) and a distal end (end on the driven portion side). Even if the torque acting on the drive shaft 40 increases in a state where the drive shaft 40 is transmitting the driving force, the hard portion Hi does not twist. By providing the hard portion Hi that does not generate twisting, the amount of twisting is reduced in each of the extended portions Ei even if the torque acting on the drive shaft 40 increases. Therefore, in the state where the drive shaft 40 transmits the driving force from the proximal end side to the distal end side, the amount of twist in the drive shaft 40 is prevented from increasing.

Further, in a state where the drive shaft 40 is rotated about the central axis S , the drive shaft 40 is twisted, so that the drive shaft 40 extends or contracts in a direction parallel to the central axis S. For example, in a state where the drive shaft 40 is rotating toward one side around the central axis S (arrow R1 side in FIGS. 2 and 3), the drive shaft 40 is contracted and the drive shaft 40 is around the central axis S. In the state of rotating toward the other side (arrow R2 side in FIGS. 2 and 3), the drive shaft 40 extends. As described above, in the present embodiment, since the drive shaft 40 is provided with the hard portion Hi, even if the torque acting on the drive shaft 40 is increased, the drive shaft 40 (each of the extended portions Ei) is twisted. The amount is smaller. Even if the torque acting on the drive shaft 40 is increased in a state where the drive shaft 40 is transmitting the driving force by reducing the amount of twist in the drive shaft 40, the extension amount and the contraction amount of the drive shaft 40 are increased. Get smaller. Therefore, in a state where the drive shaft 40 is transmitting the driving force, the drive shaft 40 is effectively prevented from extending or contracting greatly.

  As described above, in the present embodiment, when the drive shaft 40 is rotating, the amount of twist, the amount of extension, and the amount of contraction of the drive shaft 40 are kept small. Thereby, in the drive shaft 40, the transmission efficiency of the drive force from the drive source side to the driven part side is ensured.

  The drive shaft 40 is provided with an extending portion Ei having high elasticity (flexibility). For this reason, even if the hard part Hi is provided, the flexibility of the drive shaft 40 is ensured. Therefore, the flexibility of the insertion portion 5 is ensured at a portion where the drive shaft 40 extends inside the insertion portion 5 (a portion on the proximal end side with respect to the base portion 37 in the insertion portion 5).

Further, the hard portions Hi are arranged at substantially equal intervals in the direction along the central axis S. For this reason, in the state where the drive shaft 40 is rotating, the torsional stress generated by the torsion becomes substantially the same in all the extending portions Ei. Therefore, in a state where the drive shaft 40 is transmitting a driving force from the base end side (drive source side) to the tip end side (driven portion side), substantially uniformly over the entire length in the direction along the central axis S , Torsional stress acts on the drive shaft 40.

(Modification of the first embodiment)
In the first modification of the first embodiment shown in FIG. 4, in the drive shaft 40, the interval in the direction along the central axis S of the hard portion Hi is at the base end side (drive source side). Compared to the tip side (driven portion side), the area becomes smaller. That is, in the drive shaft 40 of this modification, the separation distance di in the direction along the central axis S between each of the hard portions Hi and the adjacent hard portion ( one or two corresponding to Hi) is It is smaller at the distal end side (driven portion side) than at the proximal end side (drive source side). For example, the separation distance dl between the hard part Hl-1 and the hard part Hl is smaller than the separation distance dk between the hard part Hk-1 and the hard part Hk. Thereby, in the drive shaft 40, the hard portion Hi is densely arranged at the distal end portion as compared with the proximal end portion, and the rigidity is higher than that at the proximal end portion.

In the state where the drive shaft 40 rotates around the central axis S , the closer to the rotating body 38 that is the driven portion, the larger the load acts. In the present modification, the rigid portion Hi is disposed as described above, whereby the rigidity of the portion of the drive shaft 40 where the load increases is ensured.

In the second modification of the first embodiment shown in FIG. 5, in the drive shaft 40, the interval in the direction along the central axis S of the hard portion Hi is larger than that at the tip side (driven portion side). It becomes smaller at the base end side (drive source side). That is, in the drive shaft 40 of this modification, the separation distance di in the direction along the central axis S between each of the hard portions Hi and the adjacent hard portion ( one or two corresponding to Hi) is It is smaller at the base end side (drive source side) than at the front end side (driven portion side). For example, the separation distance dk between the hard part Hk-1 and the hard part Hk is smaller than the separation distance dl between the hard part Hl-1 and the hard part Hl. Thereby, in the drive shaft 40, the hard portion Hi is densely disposed in the proximal end portion as compared with the distal end portion, and the rigidity is higher than that in the distal end portion.

  In the portion of the insertion portion 5 on the proximal end side with respect to the base portion 37, it is preferable that the flexibility becomes lower from the distal end side toward the proximal end side from the viewpoint of insertion into the lumen or the like. In the present modification, the hard portion Hi is arranged as described above, so that the flexibility of the insertion portion 5 becomes lower from the distal end side toward the proximal end side at the proximal end portion with respect to the base portion 37. It becomes easy to realize the structure which becomes.

Further, the number of the hard portions Hi is not fixed, and in one modification, only one hard portion Hi (H1) may be provided on the drive shaft 40. That is, at least one hard part (Hi) is provided between the base end (end on the drive source side) and the front end (end on the driven part side) of the drive shaft 40, and the hard part in the direction along the central axis S. What is necessary is just to be pinched | interposed into two extended parts (two which Ei respond | corresponds) each of Hi corresponds.

  Further, the number of coil layers (51 to 54) forming the drive shaft 40 is not fixed. In some variations, the drive shaft 40 may be formed from only one coil layer (54). Also in this case, in the drive shaft 40, for example, at least one hard portion Hi is formed by brazing the outer peripheral surface of the coil layer (54) over the entire circumference.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the configuration of the first embodiment is modified as follows. In addition, the same code | symbol is attached | subjected about the part same as 1st Embodiment, and the description is abbreviate | omitted.

FIG. 6 is a diagram illustrating a configuration of the drive shaft 40. As shown in FIG. 6, the drive shaft 40 of the present embodiment includes a first shaft portion 46A and a second shaft portion 46B provided on the distal end side (driven portion side) with respect to the first shaft portion 46A. And comprising. By a first shaft portion 46A, the extending portion (first extending portion) EA is formed extending along the central axis S, which extends along the central axis S by a second shaft portion 46B An extended portion (second extended portion) EB is formed. The first shaft portion 46A (extension portion EA) is formed from a plurality (four in the present embodiment) of coil layers 51A to 54A, and the second shaft portion 46B (extension portion EB) is a plurality (the present portion). In the embodiment, four coil layers 51B to 54B are formed (see FIG. 3). The outermost layer of the first shaft portion 46A is formed by the coil layer (first coil layer) 54A, and in the first shaft portion 46A, the coil layer 51A, the coil layer 52A, The coil layer 53A and the coil layer 54A are provided in this order. The outermost layer of the second shaft portion 46B is formed by the coil layer (second coil layer) 54B. In the second shaft portion 46B, the coil layer 51B and the coil layer are formed from the inner peripheral side toward the outer peripheral side. 52B, coil layer 53B, and coil layer 54B are provided in this order.

Each of the coil layers 51 </ b> A to 54 </ b> A and 51 </ b> B to 54 </ b> B is formed in a spiral shape with the central axis S as the center. The coil layer (first coil layer) 54A that forms the outermost layer of the first shaft portion 46A (extension portion EA) is the coil layer that forms the outermost layer of the second shaft portion 46B (extension portion EB). The winding direction is opposite to (second coil layer) 54B. For example, the coil layer 54A is formed in a spiral shape toward one side (the arrow R1 side in FIG. 6) around the central axis S from the base end side (drive source side) toward the tip end side (driven portion side). The coil layer 54 </ b> B is formed in a spiral shape toward the other side (the arrow R <b> 2 side in FIG. 6) around the central axis S as it goes from the proximal end side to the distal end side.

  In the first shaft portion 46A (extended portion EA), each of the coil layers 51A to 54A is adjacent to the coil layer (one or two corresponding to 51A to 54A) in the radial direction of the drive shaft 40. And the coil layers 51B to 54B are adjacent to each other in the radial direction of the drive shaft 40 in the second shaft portion 46B (extension portion EB). The winding direction is preferably opposite to the corresponding one or two). In this case, the coil layer 51A of the first shaft portion 46A is opposite in winding direction to the coil layer 51B of the second shaft portion 46B, and the coil layer 52A of the first shaft portion 46A is The winding direction is opposite to that of the coil layer 52B of the shaft portion 46B. The coil layer 53A of the first shaft portion 46A is opposite in winding direction to the coil layer 53B of the second shaft portion 46B.

Between the extending portion (first extending portion) EA of the first shaft portion 46A and the extending portion (second extending portion) EB of the second shaft portion 46B in the direction along the central axis S. Is sandwiched between the hard portions 55. Therefore, the extended portion EA is provided adjacent to the proximal end side (drive source side) of the hard portion 55, and the extended portion EB is provided adjacent to the distal end side (driven portion side) of the hard portion 55. The coil layers 51A to 54A of the first shaft portion 46A are connected to the coil layers 51B to 54B of the second shaft portion 46B via the hard portion 55.

  The hard part 55 is a pipe member made of, for example, metal. For this reason, the hard part 55 is harder than the first shaft part 46A (extension part EA) and the second shaft part 46B (extension part EB), and the first shaft part 46A and the second shaft part. It becomes a rigid body having higher rigidity than 46B. Further, the first shaft portion 46 </ b> A and the second shaft portion 46 </ b> B are elastic bodies having higher elasticity (flexibility) than the hard portion 55.

  Also in the present embodiment, the drive shaft 40 is provided with a hard portion 55 having high rigidity between the base end (end on the drive source side) and the tip end (end on the driven portion side), and the drive shaft 40 provides driving force. Even if the torque acting on the drive shaft 40 increases in the transmitting state, the hard portion 55 does not twist. For this reason, as in the first embodiment, the amount of twist in the drive shaft 40 is prevented from increasing in a state where the drive shaft 40 transmits the driving force from the proximal end side to the distal end side. Further, even if the torque acting on the drive shaft 40 is increased in a state where the drive shaft 40 is transmitting the driving force due to the small amount of twist in the drive shaft 40, the extension amount and contraction of the drive shaft 40 are increased. The amount becomes smaller.

In the present embodiment, the coil layer 54A that is the outermost layer of the first shaft portion 46A (extension portion EA) is the same as the coil layer 54B that is the outermost layer of the second shaft portion 46B (extension portion EB). The winding direction is reversed. For this reason, in a state where the drive shaft 40 rotates about the central axis S , one of the first shaft portion 46A (extension portion EA) and the second shaft portion 46B (extension portion EB) extends. The other of the first shaft portion 46A and the second shaft portion 46B contracts. For example, in a state where the drive shaft 40 is rotating toward one side (the arrow R1 side in FIG. 6) around the central axis S , the first shaft portion 46A contracts and the second shaft portion 46B extends. . On the other hand, in a state where the drive shaft 40 is rotating toward the other side around the central axis S (arrow R2 side in FIG. 6), the first shaft portion 46A extends and the second shaft portion 46B contracts. . That is, the expansion and contraction of the first shaft portion 46A is canceled out by the expansion and contraction of the second shaft portion 46B. Accordingly, in a state in which the drive shaft 40 is rotating about the central axis S, the expansion amount and a contraction amount in the direction along the central axis S of the whole of the drive shaft 40 is further reduced. Thereby, in the drive shaft 40, the transmission efficiency of the driving force from the driving source side to the driven portion side is further improved.

(Modification of the second embodiment)
Note that the number of coil layers (51A to 54A) forming the first shaft portion 46A and the number of coil layers (51B to 54B) forming the second shaft portion 46B are not fixed. In a modification, the first shaft portion 46A may be formed only from one coil layer (54A), and the second shaft portion 46B may be formed only from one coil layer (54B).

Further, if the hard portion 55 is sandwiched between the first shaft portion 46A (extension portion EA) and the second shaft portion 46B (extension portion EB) in the direction along the central axis S , the first The winding pitch in the coil layer (51A to 54A) of the first shaft portion 46A may be different from the winding pitch in the coil layer (51B to 54B) of the second shaft portion 46B. Further, the winding pitch in the coil layers (51A to 53A) other than the outermost layer of the first shaft portion 46A is the winding pitch in the coil layers (51B to 53B) other than the outermost layer of the second shaft portion 46B. The winding pitch of the outermost coil layer (54A) of the first shaft portion 46A is different from the winding pitch of the outermost coil layer (54B) of the second shaft portion 46B. It may be.

  Further, if the rigid portion 55 is sandwiched between the first shaft portion 46A and the second shaft portion 46B, the diameter of the first shaft portion 46A (the outermost coil of the first shaft portion 46A) The winding diameter of the layer (54A) may be different from the diameter of the second shaft portion 46B (the winding diameter of the outermost coil layer (54B) of the second shaft portion 46B). Further, the number of coil layers (51A to 54A) in the first shaft portion 46A may be different from the number of coil layers (51B to 54B) in the second shaft portion 46B.

In a modification of the second embodiment shown in FIG. 7, the first shaft portion 46A and the second shaft portion 46B are formed in the same configuration as the drive shaft 40 of the first embodiment. . That is, in the first shaft portion 46A, the extended portion EAi (i = 1, 2,..., N, n + 1) and the hard portion from the base end side (drive source side) to the tip end side (driven portion side). HAi (i = 1, 2,..., N) are arranged alternately and in series. In the second shaft portion 46B, the extending portion EBi (i = 1, 2,..., N, n + 1) and the hard portion HBi (i = 1, 2,..., N) from the proximal end side toward the distal end side. ) Are arranged alternately and in series. In the direction along the central axis S , the hard part 55 is the extension part (first extension part) EAn + 1 and extension part EBi on the most distal side (driven part side) in the extension part EAi. It is sandwiched between the extended portion (second extended portion) EB1 on the most proximal side (drive source side).

  The hard portion HAi is formed, for example, by brazing the outer peripheral surface of the coil layer 54A, which is the outermost layer of the first shaft portion 46A, over the entire circumference, and the hard portion HBi is the second shaft portion 46B. The outermost surface of the coil layer 54B is formed by brazing over the entire circumference. Therefore, in the present embodiment, the hard portions HAi, HBi, 55 are harder than the extended portions EAi, EBi and have a higher rigidity than the extended portions EAi, EBi. Further, the extended portions EAi and EBi are elastic bodies having higher elasticity (flexibility) than the hard portion HAi.

  In this modification, in addition to the hard portion 55, the first shaft portion 46A is provided with a hard portion HAi, and the second shaft portion 46B is provided with a hard portion HBi. Similar to the hard portion 55, even if the torque acting on the drive shaft 40 increases in a state where the drive shaft 40 is transmitting the driving force, the hard portions HAi and HBi are not twisted. Thereby, in the state in which the drive shaft 40 is transmitting the driving force from the proximal end side to the distal end side, the amount of twist in each of the first shaft portion 46A and the second shaft portion 46B is further reduced. Therefore, in a state where the driving shaft 40 transmits the driving force from the proximal end side to the distal end side, the amount of twist in the driving shaft 40 is further effectively prevented.

  Note that the hard portions HAi may be arranged at regular intervals or may not be arranged at regular intervals. Similarly, the hard portions HBi may be arranged at regular intervals or may not be arranged at regular intervals. In addition, the number of the hard portions HAi and the number of the hard portions HBi are not fixed, and only one hard portion HAi (HA1) may be provided on the first shaft portion 46A, and the second shaft portion 46B may be provided on the second shaft portion 46B. Only one hard part HBi (HB1) may be provided. Further, the hard portion HAi may be provided only on the first shaft portion 46A, and the hard portion (HBi) may not be provided on the second shaft portion 46B. Conversely, the hard portion HBi may be provided only on the second shaft portion 46B, and the hard portion (HAi) may not be provided on the first shaft portion 46A.

(Other variations)
Moreover, although the spiral unit (20) was demonstrated as an example in the above-mentioned embodiment etc. as an auxiliary tool attached to an insertion part (5), an auxiliary tool is not restricted to a spiral unit (20). In the above-described embodiment and the like, the endoscope (3) is described as an example of the insertion device, but the insertion device is not limited to the endoscope (3). For example, the above-described configuration may be applied to an insertion operation system in which a manipulator is used as an insertion device.

In the above-described embodiment, the drive shaft (40) extends inside the insertion portion (5), and the drive shaft (40) rotates around the central axis (S) , thereby being a driven portion. The rotating body 38 rotates, but is not limited to this. For example, in an electric bending endoscope in which a pulley is provided as a driven part inside the operation part, by rotating around the central axis (S) , a driving shaft (40) that transmits a driving force for driving the pulley, The configuration of the above-described embodiment or the like may be applied. In this case, the drive shaft (40) extends through the inside of a flexible universal cord (tubular portion). The pulley (driven portion) is driven by the driving force transmitted through the drive shaft (40), whereby the bending wire is pulled and the bending portion is bent.

In the above-described embodiment and the like, the drive shaft (40) extends along the central axis (S) inside the tubular portion (5), and the drive shaft (40) is driven by the drive source (32). In a state where the force is transmitted to the driven part (38), it rotates about the central axis (S) . The drive shaft (40) includes a plurality of extending portions (Ei; EA, EB; EAi, EBi) and two extending portions (two corresponding to Ei; EA, EB ) in the direction along the central axis (S). Each of which is sandwiched between EAi and EBi, and is harder than the extended portion (Ei; EA, EB; EAi, EBi) and harder (Hi; 55; HAi, HBi) , 55).

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention.

Claims (11)

A driving shaft that extends along the central axis and that is rotated around the axis of the central axis by a driving source to transmit a driving force to the driven portion;
While being extended along said central axis, and a plurality of extending portions that are arranged for a direction along the central axis,
While connecting between the ends of the two extending portions in the direction along the central axis, a hard portion formed harder than the extending portion,
A drive shaft comprising: The first extending portion provided adjacent to the drive source side of the hard portion in the extending portion includes a first coil layer formed in a spiral shape around the central axis ,
A second extending portion provided adjacent to the driven portion side of the hard portion in the extending portion is formed in a spiral shape with the central axis as a center, and is wound with the first coil layer. Comprising a second coil layer with opposite turning directions;
The drive shaft of claim 1. Each of the first extending portion and the second extending portion includes a plurality of coil layers formed in a spiral shape around the central axis ,
The first coil layer forms an outermost layer of the first extending portion,
The second coil layer forms an outermost layer of the second extending portion.
The drive shaft according to claim 2.   The drive shaft according to claim 2, wherein the first coil layer is connected to the second coil layer via the hard portion. The hard portion is a plurality of hard portions provided apart from each other in the direction along the central axis ,
The plurality of hard portions are arranged at equal intervals in a direction along the central axis .
The drive shaft of claim 1. The hard portion is a plurality of hard portions provided apart from each other in the direction along the central axis ,
The intervals between the plurality of hard portions in the direction along the central axis are smaller at a portion on the driven portion side than on a portion on the driving source side,
The drive shaft of claim 1. The hard portion is a plurality of hard portions provided apart from each other in the direction along the central axis ,
The intervals between the plurality of hard portions in the direction along the central axis are smaller at the portion on the drive source side than at the portion on the driven portion side,
The drive shaft of claim 1. The drive shaft of claim 1;
An insertion portion extending along the longitudinal axis and forming a tubular portion in which the drive shaft extends ; and
An insertion device comprising:   The insertion device according to claim 8, further comprising the drive source that is provided on a proximal end side with respect to the insertion portion and generates the drive force transmitted through the drive shaft.   The insertion device according to claim 8, wherein the insertion portion includes a driven portion that is driven when the driving force is transmitted through the driving shaft. The insertion device of claim 10;
An auxiliary tool attached to the insertion portion, wherein the driven portion is driven in a state of being attached to the insertion portion, whereby the driving force is transmitted from the driven portion;
An insertion device comprising:

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